Computer Memory
The physical address of computer memory banks may be mapped to different logical addresses for various purposes.
For example, the same physical memory may appear at two different logical addresses and if accessed by the program at one address, data will pass through the CPU cache whereas if it is accessed at the other address, it will bypass the cache.
In a system supporting virtual memory, there may actually not be any physical memory mapped to a logical address until an access is attempted. The access triggers special functions of the operating system which reprogram the MMU to map the address to some physical memory, perhaps writing the old contents of that memory to disk and reading back from disk what the memory should contain at the new logical address. In this case, the logical address may be referred to as a $ virtual address.
Read more about this topic: Logical Address
Famous quotes containing the words computer and/or memory:
“The analogy between the mind and a computer fails for many reasons. The brain is constructed by principles that assure diversity and degeneracy. Unlike a computer, it has no replicative memory. It is historical and value driven. It forms categories by internal criteria and by constraints acting at many scales, not by means of a syntactically constructed program. The world with which the brain interacts is not unequivocally made up of classical categories.”
—Gerald M. Edelman (b. 1928)
“For an actress to be a success, she must have the face of Venus, the brains of a Minerva, the grace of Terpsichore, the memory of a Macaulay, the figure of Juno, and the hide of a rhinoceros.”
—Ethel Barrymore (1897–1959)